1. Technical Field
This invention relates to a lubricant coating device and an image forming apparatus.
2. Description of Related Art
In an image forming apparatus using an electrophotographic system, a lubricant is used in order to reduce the friction between an image carrier and a cleaning blade which cleans a surface of the image carrier as well as to effectively perform cleaning. A solid-state lubricant, after being scraped away by a lubricant brush, is adhered onto the surface of the image carrier by the lubricant brush and is then pushed and spread out on the image carrier by a smoothing blade. The smoothing blade is fixed and pressed against the image carrier with a certain pressure and smoothes the lubricant on the image carrier so as to push and spread out the lubricant while the image carrier is driven to rotate around a rotation shaft.
As an art associated with the above issue, there has been a technique of providing another lubricant brush disposed in the downstream of a lubricant brush (for example, see Japanese Patent Publication No. 2010-191110). According to this technique, a lubricant scattered from the first lubricant brush is received by the second lubricant brush, and the lubricant gets adhered to an image carrier by the second lubricant brush; therefore, the lubricant that could not have been adhered by the first lubricant brush can be adhered to the image carrier. So, the waste of the lubricant is reduced.
However, in the technique disclosed in the above Japanese Patent Publication, although the lubricant can be supplied to the image carrier by the two lubricant brushes without wasting the lubricant, the supplied lubricant is pushed and spread out on the surface of the image carrier by a smoothing blade provided in the downstream of the two lubricant brushes. Since the smoothing blade scrapes away the lubricant more than necessary, the lubricant ends up being wasted anyway. Meanwhile, if an abutting force of the smoothing blade against the image carrier is reduced in order to reduce the lubricant that is scraped away and wasted, a pressure for smoothing the lubricant is reduced; thus, uniform coating of the lubricant cannot be achieved. Accordingly, transfer unevenness of toner results due to coating unevenness of lubricant on the image carrier, whereby printing quality is lowered.
See Japanese Patent Publication No. 2010-191110.